Course device for vehicles



y 7, 1 F. LAUCK 2.200.030

COURSE DEVICE FOR YEHICLES Original Filed June 25, 1937' INVENTOR.

Fm'edm'c/r L auck Tlwwmm' ATTORN EY.

Patented May 7, 1940 UNITED STATES PATENT OFFICE 2,200,030 COURSE DEVICE FOR 'vnmoms Original application June 25, 1937, N 0. 150,415. Divided and this application .[uly"28, Serial No. 287,141. In Germany Jn ne 29,

2 Claims.

This invention relates to course maintaining devices for vehicles such as aircraft and more particularly to .devices of the above type which include means responsive to the earths magnetic held and are adapted to indicate direction or to control the course of the vehicle, and is a division of applicants co'pending application, Serial No. 150,415, filed June 25, 1937.

An object of the invention is to provide a de vice of the above type which is automatically corrected to compensate for the compass deviaion caused by the metallic parts of the vehicle itself.

Another object is to provide a device of the above type having means to correct the compass variation due to the known angular variation in the earths magnetic field.

Other objects and advantages will be apparent as the nature of the invention is more fully disclosed.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself may be'better understood by referring to the following description, taken in connection with the accompanying drawing, in which one embodiment of the invention has been set forth for purposes of illustration.

In the drawing, the single figure is a perspective view, partly diagrammatic, illustrating a directional compass embodying thepresent invention.

Referring to the embodiment illustrated in the drawing, a compass is disclosed which may be of any standard type having a directional element responsive to the earth's magnetic field mounted in cooperative relation with a course member such as a compass card and which compass is suspended by links 2 and 3 from a shaft 3 in such manner that the compass remains horizontal at all times. A disc 5 is carried by the shaft't and is provided at its periphery with teeth which are engaged by a pinion 6, attached to a lever l. The lever 1 carries a roller 8 engaging a cam disc 9 which is fixed with respect to the vehicle. pinion 6 is carried on a worm wheel it which is coaxial with the shaft 4 and is coupled with the disc 5 by means of a springll which is adapted to take. up any slack or looseness between the disc5 and the pinion 6 and to hold the roller 8 against the surface of the cam disc 9.

The worm wheel I0 is adjusted by means of a worm l2, carried by a shaft I3 and controlled by a crank it actuating a shaft l3a which is con- The" nected to the shaft l3 by means of a differential gear [1. The differential gear I! comprises a disc na attached to the shaft l3 and a sleeve IIb engaging a pinion l'lc carried bythe shaft lie. The sleeve I'Ib is actuated by a gear Ild carried by ashaft He which is controlled by a crank l8. A suitable scale l5 cooperating with an index mark it is actuated by a worm i511, carried by the shaft 13a to indicate the adjustment effected by the crank M. A similar scale IQ cooperating with an index mark 20 is actuated by a worm l9a mounted on a shaft lie to indicate theadjustment effected by the crank iii.

In the operation of the above-described device, the desired course is set by adjusting the course member by means of the crank M and the scale l5. This adjustment is effected by the unitary movement of the. shafts l3 and Na which, through the worm l2 and the worm wheel it and pinion 6 cause a corresponding movement 'of disc 5 thereby displacing the housing of the compass and setting the compass to the course desired. During this adjustment the roller 8 rolls around the surface of the cam disc 9 thereby causing the pinion 6 to rotate slightly and to vary the angular position of the disc 5 by an amount dependent upon the contour of the cam disc 9. cam disc 9 is designed to compensate for the deviation caused by the vehicle itself, such as by the distribution of the magnetic masses which affect the accuracy of the compass. This cam disc 9 and associated mechanism accordingly automatically compensates for the compass deviation and eliminates this factor from consideration by the navigator.

The variation of the compass produced by the directional variation in the earth's magnetic field and which may be determined from charts or tables, is compensated for by means of the crank: it and scale it which acts through differential The gear i l to make an adjustment of the worm wheel pass in the particular localities involved. ,Hence needle without the introduction of magnetic matically connecting'the deviation of a compass masses orother correcting means which tend to distort the direction of the earths field. Means is also provided so that the variation 01 the compass can be easily corrected by the navigator; In operation, it is only necessary to make two adjustments, namely, the course adjustment effected in accordance with scale I5 and the variation adjustment which is eflected in accordance with the scale l9.

Althoughonly one embodiment of the invention has been illustrated and described, it is to be specifically understood that various changes and modifications in form, materials and relative arrangement of parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention.

Reference is therefore to be had to the appended claims for a definition of the limits of the invention.

What is claimed is: g

1. In combination with a compass, a member adapted to be adjusted in accordance with the desired course, means effecting said adjustment comprising a disc turning with said member, a pinion engaging said disc, a second disc carrying said pinion, means adjusting said second disc in accordance with the desired course and fixed cam means adapted to actuate said pinion as the two discs are turned so as to vary the relative rotation oi the two discs in accordance with the known deviations of said compass, said adjusting means including diiferentlal mechanism adapted to adjust the position of said second disc to compensate for the variation of said compass.

2'. In combination with a compass, a member adapted to be adjusted in accordance with the desired course, means eflecting said adjustment comprising a disc turning the said member, a pinion engaging said disc, 9. second disc carrying said pinion, means adjusting said second disc in accordance with the desired course, a stationary cam having a contour corresponding to the deviation of said compass at the difl'erent angular po- 

